The cases of misplaced projectors are frequent in a theater due to vibration of an air conditioning system, an audio system or the like, and when the projectors are misplaced like this, contents such as a movie, an advertisement material or the like may not be projected at a correct location on a projection surface such as a screen or a wall, and thus the audience may not be provided with a proper motion picture projection service. Accordingly, operators of a theater need to correct the projection area frequently, and conventionally, such a projection area correction has been performed manually by an engineer.
However, when the projection area correction is performed manually, accuracy of the work is lowered since the work is done by a human being, and in addition, since the work of correcting the projection area should be performed frequently in the theater, the manpower and cost consumed therefor are not small.